Co-ordinate interleaved non-orthogonal amplify and forward relaying protocol

Abstract

In this paper, we propose and analyze a coordinate interleaved non-orthogonal amplify and forward (CINAF) protocol for the single antenna half-duplex relay channel. Compared to a conventional non-orthogonal amplify and forward (NAF) protocol, the proposed protocol achieves full diversity for all transmitted symbols. The proposed precoding scheme also has the advantage of a low complexity zero forcing successive interference cancellation at the receiver compared to joint maximum likelihood decoding for an existing precoding scheme. In a cooperation frame having N symbol intervals, the conventional NAF protocol transmits N symbols. Out of these N symbols only N over 2 symbols get the full diversity gain provided by the cooperative network. The remaining N over 2 symbols do not have any diversity advantage. In order to achieve full diversity gain, we propose precoded transmission using coordinate interleaving. We prove that the proposed scheme achieves full diversity for all symbols. We also show using simulations that the proposed scheme is better in terms of performance compared to an existing precoding scheme.